Hierarchical Data and Combo Boxes

[Albert]

Using a GridView control to bind to Hierarchical Data programmatically.  One of the columns in the Child Template  is a Combo Box. One of the requirements is that the items listed in the combo box are dependent on a value from a Column in the Parent row.

 

For example, if a Column named KitNumber  in the Parent row has a value of  12345 on editing the child row, the combo box should only display the PartNumbers that are relevant to the KitNumber.  Sounds simple enough but I have not been able to figure this out using the GridView control.  Is this possible?

Any suggestions greatly appreciated.

[Martin Vasilev]

Hi Code7,

Thank you for writing.

You can implement the desired behavior by changing the editor for a chosen column in child view. You can get its parent row through GridViewInfo.ParentRow property and use any cell values for condition. Please, consider the following code as example:

void radGridView1_CellBeginEdit(object sender, GridViewCellCancelEventArgs e)
{
    RadComboBoxEditor editor = this.radGridView1.ActiveEditor as RadComboBoxEditor;
    if (editor != null)
    {
        RadComboBoxEditorElement editorElement = editor.EditorElement as RadComboBoxEditorElement;

        GridViewRowInfo parentRow = this.radGridView1.CurrentRow.GridViewInfo.ParentRow;

        if (parentRow != null)
        {
            object cellValue = parentRow.Cells["DependColumn"].Value;

            if ((int)cellValue == 1)
            {
                editorElement.DataSource = new BindingList<String>() { "Item1", "Item2" };
            }
            else if ((int)cellValue == 2)
            {
                editorElement.DataSource = new BindingList<String>() { "Item3", "Item4", "Item5" };
            }
            else
            {
                editorElement.DataSource = null;
            }
        }
    }
}

void radGridView1_EditorRequired(object sender, EditorRequiredEventArgs e)
{
    GridViewColumn currentColumn = this.radGridView1.CurrentColumn;
    if (currentColumn != null && ((GridViewTextBoxColumn)currentColumn).UniqueName.Equals("CustomColumn"))
    {
        e.EditorType = typeof(RadComboBoxEditor);
    }
}

private void Form1_Load(object sender, EventArgs e)
{
    GridViewTextBoxColumn column = new GridViewTextBoxColumn();
    column.UniqueName = "CustomColumn";
    this.radGridView1.MasterGridViewTemplate.ChildGridViewTemplates[0].Columns.Add(column);
}

Do not hesitate to contact me again if you have any other questions.

Regards,
Martin Vasilev
the Telerik team

Instantly find answers to your questions on the new Telerik Support Portal.
Watch a video on how to optimize your support resource searches and check out more tips on the blogs.

[Albert]

Thanks Martin. I have implemented this approach and have expereinced no other issues.

Thanks again!

[Albert]

Say Martin...on another issue...Is it possible to cancel the row dropdown for the Childrow? So that if there are no childrows for a row don't show the childrow.

Thanks,

[Martin Vasilev]

Hello Code7,

Thank you for getting back to me.

You can easily implement this by using the ChildViewExpanding event. Please take a look to the following code snippet:

void radGridView1_ChildViewExpanding(object sender, ChildViewExpandingEventArgs e)
{
    GridViewRowInfo[] rows = e.ParentRow.ViewTemplate.ChildGridViewTemplates[0].GetChildRows(e.ParentRow);
    if (rows == null || rows.Length <= 0)
    {
        e.Cancel = true;
    }
}

Write me back if you have any other questions.

All the best,
Martin Vasilev
the Telerik team

Instantly find answers to your questions on the new Telerik Support Portal.
Watch a video on how to optimize your support resource searches and check out more tips on the blogs.

[Albert]

Excellent. That worked.

[Jeff]

This doesn't seem to work anymore. Can anyone point me to documentation on this?

[Stefan]

We sure can. Here is a link to a KB with an example of this: http://www.telerik.com/support/kb/winforms/gridview/details/cascading-comboboxes-in-radgridview.

I hope this helps.

Regards,
Stefan
Telerik